A cost-effective and humidity-tolerant chloride solid electrolyte for lithium batteries

Li-ion-conducting chloride solid electrolytes receive considerable attention due to their physicochemical characteristics such as high ionic conductivity, deformability and oxidative stability. However, the raw materials are expensive, and large-scale use of this class of inorganic superionic conductors seems unlikely. Here, a cost-effective chloride solid electrolyte, Li 2 ZrCl 6 , is reported. Its raw materials are several orders of magnitude cheaper than those for the state-of-the-art chloride solid electrolytes, but high ionic conductivity (0.81 mS cm –1 at room temperature), deformability, and compatibility with 4V-class cathodes are still simultaneously achieved in Li 2 ZrCl 6 . Moreover, Li 2 ZrCl 6 demonstrates a humidity tolerance with no sign of moisture uptake or conductivity degradation after exposure to an atmosphere with 5% relative humidity. By combining Li 2 ZrCl 6 with the Li-In anode and the single-crystal LiNi 0.8 Mn 0.1 Co 0.1 O 2 cathode, we report a room-temperature all-solid-state cell with a stable specific capacity of about 150 mAh g –1 for 200 cycles at 200 mA g –1 . Stable inorganic solid electrolytes are instrumental in developing high-voltage Li metal batteries. Here, the authors present the synthesis and electrochemical energy storage properties of a cost-effective and humidity-tolerant chloride solid electrolyte.